Passenger cars can have a roof rack system on their roof in the form of a roof rack or a roof rail. These roof rack systems consist specifically of two retaining fixtures located parallel to one another, where under the present patent application a roof rack is understood to mean a system with feet at the lateral ends and, where required, center feet, that is to say, the system is located at a distance from the roof of the motor vehicle because of the end feet and the center feet. The roof rails mentioned refer to a system which does not have end feet and center feet, that is to say the roof rails run accordingly directly on the upper side of the roof of the vehicle. Cross bars can preferably be attached between the two roof rack elements or roof rail elements running spaced apart from each other to create additional support and carrying capacity for fastening a load on the roof of the motor vehicle.
Since a roof rack system of this type has to be attached to the roof of the motor vehicle, a connection is made by means of an attaching device to load-bearing parts in the roof of the vehicle. This is usually done while the vehicle is being manufactured, that is to say, the roof rack systems mentioned here are usually assigned to the motor vehicle from the start and are not removed when the vehicle is in use. The invention addresses such systems, but comprises also possible systems which can be installed or removed as required. In each case it is necessary to effect the attachment of the roof rack system to the vehicle roof with a fastening device which passes through the roof skin using mounting bolts and is connected to corresponding load-bearing roof parts. Piercing the roof skin carries the risk that moisture can penetrate into the vehicle roof.